EP1255685 describes a cartridge for use in a beverage preparation machine for dispensing an espresso-style coffee beverage. The cartridge comprises one or more restrictions for forming a jet or jets of beverage. At least one air inlet is provided and the jet (or jets) of beverage is passed over said at least one air inlet to thereby draw up air through the air inlet and entrain air bubbles in the flow of beverage. The flow of beverage then passes along an expansion chamber to an outlet where it is dispensed. In one embodiment, the cartridge further comprises within the beverage flowpath a surface upon which the beverage impinges.
EP1440903 also describes a cartridge for use in a beverage preparation machine for dispensing an espresso-style coffee beverage. The cartridge comprises an eductor having an air inlet, and means for forming a low pressure jet of beverage which is passed over said air inlet to thereby draw up air through the air inlet and entrain the air bubbles in the flow of beverage.
Whilst the cartridges described in EP1255685 and EP1440903 have been found to be effective, it would be desirable to produce an improved cartridge wherein the quality of the crema delivered into the cup is improved and/or controlled.